Ok, Here is an oldie, second side o a duplexed copy on the 3035 is light. I remember this issue but not the fix. Any suggestions? Thanks.

Transfer Roller.

firmware

Mod-kit

second that....firmware.

setting conveying unit as old style makes it darker

Bring the firmware up to current level and replace the transfer roller. This was one of the first problems I had when I started working on Kyocera's. There is a tech bulletin somewhere on KMA Connect that talks about it.

If 2/3rd's of the second side is washed out, it's the transfer roller. As they wear out, static build up on the second pass discharges as the paper hits the frame below the fuser. From that point on the last 2/3rd's of the copy is severely light.
Z

Clean the transfer roller with a lint free rag.